In integrated circuit design, engineering change order (ECO) is the process of inserting a logic change directly into the integrated circuit after the design of the integrated circuit has already been processed (e.g., after tape-out). Typically, to accommodate such modifications, extra logic may be incorporated into the design of the integrated circuit so the corresponding logic can be added to the design of the integrated circuit if required by an ECO. In some instances, integrated circuit design may involve the use of cells. Cells are structures that have a predefined pattern within the integrated circuit. Since a predetermined library of cells may be stored, this approach to design is beneficial because it is not necessary to design each individual gate within the integrated circuit. Rather, during the physical layout of the integrated circuit, the designer breaks down a new circuit design into a number of known cell designs and then combines these cells appropriately to generate a circuit that performs a desired function.
During the physical layout, cells referred to as bases or ECO bases may be included within the layout. ECO bases are designed without specific logic, but are configurable to provide the desired logic function. Although the inclusion of ECO bases is an improvement over merely incorporating extra logic elements into the integrated circuit layout, both structures can be difficult to interconnect with the remaining portions of the integrated circuit design since there may be significant routing necessary to make needed interconnections.